Venom composition of the Iberian adder (Vipera seoanei) from northern Portugal reveals limited sex and size variation

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  Venom composition of the Iberian adder (Vipera seoanei) from northern Portugal reveals limited sex and size variation Abstract Snake venom is a complex and dynamic ecological trait, with high potential for intraspecific variation. In this study, the venom composition of the Iberian adder ( Vipera seoanei ) from the Peneda Mountains of northern Portugal was investigated to explore whether venom varies with body size and sex. Venom proteomes from six individuals representing juvenile, subadult, and adult males and females were characterised using LC–MS/MS, while individual variation was assessed from SDS–PAGE profiles of 18 snakes. LC–MS/MS identified 144 proteins, dominated by phospholipases A 2 (PLA 2 ), snake venom serine proteases (svSP), and C-type lectin-related proteins (CTL). Descriptive comparisons revealed contrasting individual profiles, particularly between the juvenile male, characterised by high svSP and svMP abundance, and the juvenile female, characterised by high ...

From sting to pacemaker: a case of complete heart block following yellow scorpion envenomation—a case report

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From sting to pacemaker: a case of complete heart block following yellow scorpion envenomation—a case report

Abstract

Background

Scorpion envenomation is a significant medical concern in tropical and subtropical regions, with cardiovascular complications being among its most severe manifestations. While scorpion venom-induced cardiac dysfunction is well-documented, complete atrioventricular (AV) block is a rare occurrence. This case highlights a unique presentation of complete heart block following a yellow scorpion sting, emphasizing the importance of early recognition and management.

Case presentation

A 56-year-old Middle Eastern (Iranian) male presented to the emergency department with dizziness, syncope, and severe bradycardia following a yellow scorpion sting. Electrocardiographic evaluation revealed a complete atrioventricular block. Laboratory findings indicated elevated cardiac biomarkers, suggesting myocardial injury. Echocardiography demonstrated left ventricular dysfunction without significant structural abnormalities. The patient required temporary transvenous pacing for hemodynamic stabilization and was managed with supportive care, including intravenous fluids, atropine, and continuous cardiac monitoring. Over the course of hospitalization, his conduction abnormality resolved by permanent pacemaker, and he was discharged in stable condition.

Conclusions

This case underscores the potential for severe cardiac complications following scorpion envenomation, particularly conduction disturbances such as complete atrioventricular block. Although rare, healthcare providers should be aware of this life-threatening consequence and initiate prompt intervention to prevent adverse outcomes. Increased awareness and timely management can significantly improve prognosis in affected patients.

Zibaeenezhad, M.J., Alizadeh, Z., Rajabi, A. et al. From sting to pacemaker: a case of complete heart block following yellow scorpion envenomation—a case report. J Med Case Reports 19, 620 (2025). https://doi.org/10.1186/s13256-025-05687-0